A light emitting diode (LED) is a semiconductor device which is able to emit light of various colors due to electron-hole recombination occurring at a p-n junction between p-type and n-type semiconductors when current is applied thereto. Such an LED is advantageous over a filament-based light emitting device in that it has a relatively long lifespan, low power consumption, superior initial-operation characteristics, and the like. These factors have continually boosted the demand for LEDs. Notably of late, a great deal of attention has been given to group III nitride semiconductors that can emit light in a blue/short wavelength region.
Since the development of nitride semiconductor devices, technical advances to broaden the range of applications thereof have been made. Thus, many studies are being conducted into determining how to utilize nitride semiconductor devices in general lighting apparatuses and electrical lighting sources. According to the related art, nitride light emitting devices have been used as components employed in low-current, low output mobile products. However, of late, the range of applications of nitride light emitting devices has been broadened to encompass the field of high-current, high-output products. Accordingly, research into improvements in light emitting efficiency and the quality of semiconductor light emitting devices is being actively carried out. Particularly, light emitting devices having various electrode structures are being developed in order to improve light output amounts and reliability thereof.